1. Field of the Invention.
This invention relates to fluid pressure relief valves utilizing a slender column having a predetermined collapsible or buckling point value for releasing excess pressure above a predetermined value and more particularly to a method of making a plurality of interchangeable buckling pins each having a predetermined buckling point different from the buckling point of companion buckling pins.
Relief valves are conventionally used in industrial fluid pressure systems for the purpose of safety and protecting operating personnel as well as equipment and preventing pollution of the environment. Pressure relief valves utilizing a slender pin or column as a collapsible or buckling pin in accordance with Euler's law for releasing excess pressure have been in use for several years. The slender column or buckling pin is usually contacted at one end by one end portion of a piston-like member facing a fluid column at its other end and having a seat or seal within a sleeve or cylinder allowing slight movement of the piston in a pin buckling direction as the pin initially bends elastically, slightly, prior to releasing fluid pressure without the piston seal with its seat being opened.
This type of pressure relief valve and its associated buckling pin are usually made or fabricated for a particular pressure setting and since the end mountings of the buckling pin are critical to monitoring and releasing excess fluid pressure at a predetermined value retrofitting such a valve with a buckling pin having a different pressure release valve is not easily accomplished.
This problem is obviated by the hereinbelow described method of making interchangeable buckling pins for selecting a predetermined pressure release value for a given pressure relief valve.
2. Description of the Prior Art.
The most pertinent patent is believed to be my U.S. Pat. No. 4,724,857 issued Feb. 16, 1988 for PRESSURE RELIEF VALVE. This patent discloses a plurality of different buckling pins which may be used in this valve for monitoring pressure. However, all of the disclosed buckling pins have identical pressure setting values which buckle by movement of the piston toward an opening direction of the piston in response to a predetermined pressure value against the piston.
U.S. Pat. No. 5,067,511 issued Nov. 26, 1991 to Taylor for HIGH PRESSURE FLUID EMERGENCY SHUT OFF VALVE and U.S. Pat. No. 5,146,492 issued Sep. 15, 1992 issued to Taylor for LOW PRESSURE FLUID EMERGENCY SHUT DOWN VALVE are believed good examples of the further state-of-the-art.
U.S. Pat. No. 5,067,511 discloses fluid flowing through a right angular valve body containing a normally open valve having its stem supporting one end of a collapsible pin and moved toward the pin by excess fluid pressure acting against the unbalanced valve stem area for buckling the pin in response to excess pressure and seating the valve closing fluid flow through the fluid passageway.
The other U.S. Pat. No. 5,146,942 similarly discloses a right angle valve body forming a fluid passageway and containing a valve having a stem connected with a diaphragm in a diaphragm chamber and bearing against the end of a collapsible or buckling pin so that excess pressure in the diaphragm chamber opposite the pin biases the diaphragm toward the pin to collapse or buckle the pin and move the valve toward its seat closing the flow passageway.
This invention is distinctive over the above named patents by disclosing a method of making interchangeable buckling pins each having an individual pressure rating which is capable of retrofitting any one of the above named patents and including the valve disclosed by this invention.